Actress Hayden Panettiere's death is under investigation. She was 36 years old. Authorities found her unresponsive and in cardiac arrest after a 911 call.

The federal agency responsible for enforcing drug laws is now involved in the investigation. Further information about the circumstances surrounding her death can be found through news reports.

Panettiere had been open about her personal struggles, including addiction and mental health issues. Details about the investigation and its findings are available from news sources.